playing with different size blocks is a great time for a design wall, but if you don't have one just lay them out on a bed or the floor...when i did my first one i simply layed all of the different size blocks out, on the floor and started rearranging them with gaps here and there...when i liked the way they were i looked at the spaces around them that needed to be filled, then i made some blocks for some areas, like small pinwheels in a strip; some checkerboard squares, piano keys, flying geese, a couple plain squares...just ...'built a quilt' it was wonderful creative fun!